From 8105c14454f8c4f575f16b44ec616ffd045be57f Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Tue, 31 Jul 2018 22:14:56 +0300
Subject: Improve debug_dump performance

---
 src/algo/walk.rs |  4 +--
 src/lib.rs       |  2 --
 src/utils.rs     | 76 +++++++++++++++++++++++++++++---------------------------
 3 files changed, 41 insertions(+), 41 deletions(-)

(limited to 'src')

diff --git a/src/algo/walk.rs b/src/algo/walk.rs
index c6d050251..a50ec2a09 100644
--- a/src/algo/walk.rs
+++ b/src/algo/walk.rs
@@ -8,12 +8,12 @@ pub fn preorder<'a>(root: SyntaxNodeRef<'a>) -> impl Iterator<Item = SyntaxNodeR
 }
 
 #[derive(Debug, Copy, Clone)]
-enum WalkEvent<'a> {
+pub enum WalkEvent<'a> {
     Enter(SyntaxNodeRef<'a>),
     Exit(SyntaxNodeRef<'a>),
 }
 
-fn walk<'a>(root: SyntaxNodeRef<'a>) -> impl Iterator<Item = WalkEvent<'a>> {
+pub fn walk<'a>(root: SyntaxNodeRef<'a>) -> impl Iterator<Item = WalkEvent<'a>> {
     let mut done = false;
     ::itertools::unfold(WalkEvent::Enter(root), move |pos| {
         if done {
diff --git a/src/lib.rs b/src/lib.rs
index 953c9b860..a72d9e3cb 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -41,8 +41,6 @@ pub use {
     yellow::{SyntaxNode, SyntaxNodeRef, SyntaxRoot, TreeRoot},
 };
 
-pub(crate) use yellow::SyntaxError;
-
 pub fn parse(text: String) -> SyntaxNode {
     let tokens = tokenize(&text);
     parser::parse::<yellow::GreenBuilder>(text, &tokens)
diff --git a/src/utils.rs b/src/utils.rs
index f99d31b36..327d89a24 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -1,46 +1,48 @@
-use std::{collections::BTreeSet, fmt::Write};
-use {SyntaxError, SyntaxNode, SyntaxNodeRef};
+use std::{fmt::Write};
+use {
+    SyntaxNode,
+    algo::walk::{WalkEvent, walk},
+};
 
 /// Parse a file and create a string representation of the resulting parse tree.
 pub fn dump_tree(syntax: &SyntaxNode) -> String {
     let syntax = syntax.as_ref();
-    let mut errors: BTreeSet<_> = syntax.root.errors.iter().cloned().collect();
-    let mut result = String::new();
-    go(syntax, &mut result, 0, &mut errors);
-    return result;
-
-    fn go(
-        node: SyntaxNodeRef,
-        buff: &mut String,
-        level: usize,
-        errors: &mut BTreeSet<SyntaxError>,
-    ) {
-        buff.push_str(&String::from("  ").repeat(level));
-        writeln!(buff, "{:?}", node).unwrap();
-        let my_errors: Vec<_> = errors
-            .iter()
-            .filter(|e| e.offset == node.range().start())
-            .cloned()
-            .collect();
-        for err in my_errors {
-            errors.remove(&err);
-            buff.push_str(&String::from("  ").repeat(level));
-            writeln!(buff, "err: `{}`", err.message).unwrap();
-        }
+    let mut errors: Vec<_> = syntax.root.errors.iter().cloned().collect();
+    errors.sort_by_key(|e| e.offset);
+    let mut err_pos = 0;
+    let mut level = 0;
+    let mut buf = String::new();
+    macro_rules! indent {
+        () => {
+            for _ in 0..level {
+                buf.push_str("  ");
+            }
+        };
+    }
 
-        for child in node.children() {
-            go(child, buff, level + 1, errors)
+    for event in walk(syntax) {
+        match event {
+            WalkEvent::Enter(node) => {
+                indent!();
+                writeln!(buf, "{:?}", node).unwrap();
+                if node.first_child().is_none() {
+                    let off = node.range().end();
+                    while err_pos < errors.len() && errors[err_pos].offset <= off {
+                        indent!();
+                        writeln!(buf, "err: `{}`", errors[err_pos].message).unwrap();
+                        err_pos += 1;
+                    }
+                }
+                level += 1;
+            },
+            WalkEvent::Exit(_) => level -= 1,
         }
+    }
 
-        let my_errors: Vec<_> = errors
-            .iter()
-            .filter(|e| e.offset == node.range().end())
-            .cloned()
-            .collect();
-        for err in my_errors {
-            errors.remove(&err);
-            buff.push_str(&String::from("  ").repeat(level));
-            writeln!(buff, "err: `{}`", err.message).unwrap();
-        }
+    assert_eq!(level, 0);
+    for err in errors[err_pos..].iter()  {
+        writeln!(buf, "err: `{}`", err.message).unwrap();
     }
+
+    return buf;
 }
-- 
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